A shelf bracket according to one of the prior arts is disclosed in JU7-15476 (Japanese Utility Model Application Publication No. 15476/1995). This prior shelf bracket is an improvement on the conventional shelf bracket shown in FIG. 10.
The shelf bracket shown in FIG. 10 comprises a support board 41 to support a shelf board 3 thereon and a generally reverse L-shaped forcing board 42 extending from the base end of the support board 41 to receive the shelf board 3 together with the support board 41. The shelf bracket is attached to a wall body W by securing a generally triangular base 43 formed integrally with the support board 41 by wooden screws or the likes to the wall body and the shelf board 3 is secured to one or both of the forcing board 42 and the support board 41 by a not shown screw or screws.
However, since the prior shelf bracket attaches the shelf board 3 by inserting one side end of the shelf board 3 between the support board 41 and the forcing board 42 of the shelf bracket, which is previously secured to the wall body W at its high position, the operation has to be made at the high position, which causes the poor effectiveness of the operation and in addition, if the shelf board could not be engaged between the support board 41 and the forcing board 42 by the cause of the size error, then the one side end of the shelf board 3 should be adjusted in its thickness by shaving it. If the degree of shaving would be inaccurate, the shaving operation had to be repeated, which disadvantageously causes the substantial operation time and labor to be consumed.
If the shelf board would be too shaved, another new shelf board 3 should be used and there was required a remarkable size precision of the shelf bracket and the shelf board 3 produced separately from each other because the sizes of them should accord with each other. Accordingly, the manufacture of them was troublesome and also the accordance of the sizes should be fully care of when the shelf board and the shelf bracket should be bought.
The shelf bracket disclosed in the aforementioned patent document has been proposed in order to delete such disadvantages and is shown in FIG. 11.
This shelf bracket does not comprise a united single member, but comprises an upper member B1 and a lower member B2, which can relatively move upward and downward by slipperily engaging an elongated protrusion b21 of the lower member B2 with a longitudinal groove b11 of the upper member B1. Thus, as the upper member B1 upwardly moves relative to the lower member B2, a distance L between a shelf board holding upper board portion b12 of the upper member B1 and a shelf board holding lower board portion b22 of the lower member B2 can be so adjusted as to accord with the thickness of the shelf board 3. In this state, the upper member B1 and the lower member B2 are securely attached to the wall body W by threadedly thrusting into the wall body W screws 2 extending through respective holes b13 and b23 in the upper and lower members B1 and B2.
In this manner, the shelf bracket disclosed in the patent document can positively support the shelf board 3 by engaging the shelf board 3 between the upper and lower holding board portions b12 and b22 of the upper and lower members B1 and B2 while maintaining the distance L between the upper and lower holding board portions b12 and b22 obtained by adjusting the space between them in accordance with the shelf board to be attached onto the shelf bracket and threadedly thrusting screws 5 extending through screw extension holes b13 in the upper holding board portion b12.
In this prior shelf bracket, since the distance L between the upper and lower holding board portions b12 and b22 can be analogously adjusted in spite of variation in the thickness of the shelf board 3, the shelf bracket can be adjusted in accordance with the shelf board 3 in site either for the thicker shelf board 3 as shown in FIG. 11A or for the thinner shelf board 3 as shown in FIG. 11B and therefore it is advantageously not required to shave the shelf board 3.
However, the prior shelf bracket disclosed in this patent document has various problems as described hereinafter.
This prior shelf bracket is secured to the wall body W by threadedly thrusting the screw 2 into the wall body W when the distance L reaches a predetermined value by adjusting the distance L to the predetermined value by slipperily moving the upper member B1 in an upward direction or the lower member B2 in a downward direction while the upper and lower members B1 and B2 are maintained to be forced against the wall body W in the state where the upper and lower holding board portions b12 and b22 of the shelf bracket are slipperily engaged with each other.
However, since the aforementioned operation is made at a high place, it will take substantial time to threadedly thrust the screw 2 while maintaining the size precision of the distance L and also the operation itself gets troublesome. In addition thereto, in some cases, the distance L would require its readjustment and in case where the shelf board should be replaced by that having the different thickness, the former shelf board 3 is removed, the screw 2 is withdrawn and thereafter the replaced shelf board 3 has to be attached, but since all of these operations should be done at the high place, the effectiveness of the operations gets disadvantageously lower.
One of the objects of the invention is to provide a shelf bracket adapted to be able to adjust a distance between board upper and lower holding board portions of upper and lower members at a lower place in order to accord this distance with the thickness of the shelf board to be held between the upper and lower holding board portions.
Another object of the invention is to provide a shelf bracket adapted to positively hold a shelf board with high reliability without loosing the shelf board relative to the upper and lower holding board portions of upper and lower members.
Further object of the invention is to provide a shelf bracket adapted to securely attach a shelf board to upper and lower holding board portions of upper and lower members at the same time when the distance between the upper and lower holding board portions is adjusted in order to accord the distance with thickness of the shelf board to be held between the upper and lower holding board portions.
Further object of the invention is to provide a shelf bracket adapted to positively support a shelf board between upper and lower holding board portions of upper and lower members even though it has a small thickness.